مجله سامانه های سطوح آبگیر باران
سال سوم شماره 1 (پیاپی 6، بهار 1394)

Assessment of flood phenomena and street floods in runoff transmission network basins shows that in some cases rainwater transmission channels cannot transmit current flow after a while - especially during peak flow- due to an increase in impervious surfaces, particularly owing to some changes in physiographic characters of the basin.. To solve such problems, many research efforts have been undertaken and practical procedures have been implemented. Delay ponds are one of the methods to solve these problems. Other optimal management strategies, BPMs, which can be used depending on the technical and economic conditions in order to solve such problems are biological remain systems, porous coating of streets, vegetative swale, etc. In this paper, a review of literatures is presented and then our research procedure is presented. Then some issues such as drainage network modeling process in the SWMM software environment are presented. The modeling procedure has been done in Status quo coupled with using delay ponds, in order to find the routes in the network and compare both waterways hydrograph (with and without delay ponds), hydrograph of the individual components in existing networks as well as using the network with delay ponds. It was observed that using delay ponds could be effective especially in limited urban areas. And it can reduce the peak hydrograph flow, increase the peak flood time and as a result, control and optimize management of flood. For this purpose during a two-stage modeling, two and three places were positioned for the construction of flood control basins. It is shown that in case of using two and three basins, the peak discharge were is reduced by 31% and 38%, respectively.

With the deployment of the belt on the land, increasing population and the need for new water resources, the need for better exploitation of all available water resources, including groundwater, surface runoff from rainfall is required. For efficient and effective use of rainwater, the role of catchments in supplemental irrigation have been reviewed by several professors and have been approved of. Therefore, in this article, calculation of the amount of water collected from the annual rainfall on the cover of greenhouses or in case of need and calculating the level of isolation required to meet the water requirements of the plants (with regard to methods to prevent evaporation of water collected) has been carried out. And the exclusion of the most critical regions of the Khorasan Razavi province, lack of access to adequate water supplies and the high life Geomembrane panels, rain water harvesting has very clear economic justifications. On the other hand, the dry land without the proper use of the method and construction of greenhouses, increasing land productivity and output and employment in the region are affected. In this way, according to the water requirement of plants grown in the greenhouse to collect rainwater in the upper level of the house and part of the adjacent land (according to the average rainfall in Mashhad and the amount of water extracted from), which is insulation for Geomembrane in pools of water for irrigation at the right time to reaffirm the measures used. Yet the implementation of this technique requires testing on health and long-term water quality monitoring will.

Flood is a natural phenomenon whose occurrence, severity and frequency depended on several factors which change due to climatic, natural and geographical conditions of each zone. The importance of understanding water resources and lack of acceptable network of hydrometric stations indicate the necessity of use of indirect methods to calculate runoff volume. The Shahroud watershed extends from the north highlands of Birjand to the eastern domain of highlands and in terms of the country’s watershed division it is considered as a part of the Loot watershed. The main reasons for increased flooding in the Shahroud watershed are changes in natural land use, illegal construction of buildings upstream of the watershed and illegal construction of buildings near the canals in recent years. In this research, the surface storage parameters of the watershed are determined based on geological maps and identification of material and kind of watershed stones. Then a map of areas prone to flooding is prepared based on the watershed geologic, petrology, hydrology and hydrogeology parameters. Based on the results of this study, only four cubic Kilometers from the whole watershed (0.25 percent of the whole watershed) are regions with low flooding potential and 1344 cubic Kilometers from the whole watershed (84 percent of the whole watershed) are regions with high and very high flooding potential. Therefore, identification of the areas of the Shahroud watershed that are prone to flooding could help in terms of soil conservation and reduction of flood damages and provides the possibility of proper management of the watershed.

The Birjand plain is located in the south Khorasan province and its area is about 3425 square Kilometers. This plain has no significant surface water resources due to the inappropriate climatic conditions and evaporation intensity. The flow of water flow is seasonal or periodic and weak and there are some narrow rivers with a constant flow in other parts of the river network. Therefore, groundwater resources are the most important water resources that maybe used in this region. Groundwater has a substantial role in economic activities and saving water in underground reservoirs requires a lower economic investment. However, the increasing demand and excessive extraction of water has caused shortages in the alluvial aquifers in all plains of the province and consequently this has led to a substantial drop in the level of water in the aquifers. Since the rain in this is negligible and at times it leads to destructive floods, the operation of artificial feeding of ground water can be an appropriate method for optimum usage of floods and ground water stability. Selecting the criteria and suitable method is of great importance for the operation of artificial feeding. In this study, the analytical hierarchical process and weighted linear combination has been used. By choosing the Birjand plain as a case study, the slope, fault, flooding potential, land use, settlements and water quality criteria have been considered for selecting the appropriate places for artificial feeding. The artificial feeding ability map is divided into 5 categories according to natural features. The results indicated that 148.93 square Kilometers are in the very unsuitable category, 339.73 square Kilometers are in the unsuitable category, 453.49 square Kilometers are in the medium suitable category, 222.83square Kilometers are in the suitable category and 142.53 square Kilometers are in the very suitable part of the studied area.

The crescent structure is one of the water harvesting systems that lacks precision in design, especially in the precision of intake volume of the crescent that may cause damage. The study area includes sloped lands in which figs are grown through dry farming by using the runoff that is collected by the crescent structure. The purpose of this study is to optimize the dimensions of crescent pond structures in Estahban of Fars province. Therefore, a maximum of 24-hour rainfall data for 20 years (1995-2014) from the Estahban station was used in this study. After analyzing the data in terms of accuracy and homogeneity, the time series data were fitted to different functions and after selecting the best distribution function with respect to residual sum of squares, the maximum 24hour rainfall on different return period was calculated. Then, the SCS method was used for calculating the runoff and based on of the 100 square meters area of each micro catchment, the volume of runoff was calculated. The results showed that the use of the log Pearson type ΙΙΙ distribution parameters is the best compared with other functions. By selecting a return period of 10 years as the basis for design and considering the different slopes, the volume of the crescent structure must have a capacity exceeding 2.33 cubic meters in order to increase the likelihood of success for the project.

The purpose of this research is identification of the capabilities of drainage basin beneficiaries who make an appropriate environment for the exploitation of natural areas through utilization of past experience. A wide range of pastures of the country are located in the arid and semi-arid regions and their water resource management is more important than that of other regions due to the limitations of drinking water and the fragility of the pasture’s ecosystems in these regions. Thus, it is very important economically and environmentally as one of the important tools for producing wealth in the objectives of resistive economy. Water shortage, excessive water or its inaccessibility in pastures will lead to non-essential use of this highly valuable resource. The current pattern of water consumption is incompatible with the arid climate in Iran. It also creates obstacles for achieving the country’s goals for development goals and makes them difficult to achieve. The only suggested solution for solving this problem is controlling and inhibiting surplus water and floodwaters from rainfalls with the aim of accumulating rainwater in pastures. In this research, the methods used for collecting rainwater include pitting, embankment, terracing, water cisterns and Faroes.The purpose of this research is the assessment of the effect of the operation of rain water catchments on the economic returns of arid and semi-arid regions along with optimal productivity of pastures in order to implement the aims of the objectives of resistive economy in natural resources sector. This assessment is conducted by using two methods of internal return rate (IRR) and benefit-cost ratio (BCR). The results showed that according to the project’s profitability (2.04 percent) and internal return rate (0.63 percent), the obtained BCR index is larger than one. Therefore, implementation of the project is justified and it brings high income for ranchers living near the project area. According to the obtained results, the reason is 60 percent due to increased production by the use of corrective actions and 35 percent due to the protection which indicates the positive impact of different corrective actions on vegetation and pastures soil.

Water is a unique resource and a vital material. Limitation of this vital material influences the capacity of other vital resources like food, energy and wild life. The per capita extraction of water is decreasing in some of the poorest and richest countries of the world due to environmental reasons, increasing costs and scarcity of water. It has to be considered that the distribution of water flow is not uniform in the world and water flow is not distributed proportional with population. Iran is not an exemption to this rule several steps have been taken to decrease the use of drinking water for irrigation purposes and use non-drinkable water especially in South Khorasan province which has the least average of rainfall. Steps toward decreasing consumption of drinkable water has been taken at green space. Also, the city hall of Qaen has started the enforcement of a plans of drinking water separation from water consumption that is used for the irrigation of plants and use of non-drinkable water for watering the trees, grass and the plants. In this research, plan of drinkable water separation from water consumption of the city of Qaen's green space from two economic sides and measuring of drinking water consumption are considered. The result shows that, the most deduction of drinking water consumption in the year 1388 is about 67 percent. In the year 1390 about 45 percent and in the year 1389 about 32.8 percent had a reduction of urban drinking water consumption. In the first three years of the implementation of this plan reduction of expenses of about 2298 million Rials was achieved considering the fact that reduction of expenses is a very important issue in the implementation and performance of this system for the city hall.